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A323705
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Odd primes p such that ((p+1)/2)^(p-1) == 1 (mod p^2).
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0
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OFFSET
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1,1
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COMMENTS
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The corresponding sequence when (p+1) in the congruence is replaced with (p-1) seems to be A125854.
a(4) > 4262937421 if it exists.
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LINKS
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MATHEMATICA
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Select[Prime[Range[718*10^4]], PowerMod[(#+1)/2, #-1, #^2]==1&] (* Harvey P. Dale, May 14 2021 *)
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PROG
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(PARI) forprime(p=3, , my(x=(p+1)/2); if(Mod(x, p^2)^(p-1)==1, print1(p, ", ")))
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CROSSREFS
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KEYWORD
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nonn,hard,bref,more
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AUTHOR
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STATUS
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approved
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